This invention relates generally to flow control devices, and, more particularly to a pressure sensitive regulating valve.
In the field of rocketry or any other area which undergoes a great variance in pressure, it is essential to provide flow control devices which are not only sensitive to these changes in pressure but is also extremely reliable in action. Heretofore the valves which were used in these areas were complex in nature, relatively expensive to produce and because of their complexity, in many instances, failed during operation.
There are many instances in which a reliable flow regulator is essential, for example, one such instance is in certain gas turbine engine applications, such as ground-to-air missiles. With this type of missile the engine is started and brought up to maximum speed on the ground by the use of auxiliary equipment that is disconnected before the missile is launched. The missile fuel system may be very simple as compared to the auxiliary equipment; for example, it may comprise merely of a pressurized fuel tank mounted near the front of the engine and an inexpensive, slow reacting, pressure responsive governor located just upstream of the nozzle that discharges fuel into the engine burner chamber which is at the ambient pressure. While it is desired to maintain the fuel flow to the engine constant once the missile is launched, the missile is accelerated throughout its mission and any "G" loading in fuel lines parallel to the direction of flight causes an excessive fuel supply that may cause the engine to overspeed and overheat. It is in this area in which a reliable pressure sensitive regulating valve becomes necessary.
Another example in which such a pressure dependent valve is essential, is in the transpiration cooling of a re-entry vehicle which is accomplished by forcing a coolant through the nose of the vehicle in quantities adequate to maintain nose temperatures within an acceptable range. The amount of coolant required is a function of the aerodynamic heating encountered. In order to keep the quantity of coolant carried and the size and weight of the expulsion system low, a means of controlling the flow to match the requirements is necessary. Since the aerodynamic heating of the vehicle is caused by the compression of the atmosphere ahead of the vehicle, it is obvious that there will be a correlation between the heating rate and the deceleration of the vehicle which is a result of the pressure force thereon. This deceleration is sensed by a pressure sensitive valve which meters a predetermined flow to the nose.
Heretofore, means of flow control resulted in prohibitive quantities of coolant or fuel to be carried in the vehicle as well as constant malfunction during critical stages of operation.